Various synthetic resins are much used in various fields in our daily life. As for electric appliances, for example, many small and large synthetic resin parts are used therein. However, as being mostly made of organic materials, synthetic resin parts are combustible and give much heat of combustion. Therefore, those synthetic resin parts are problematic in that, if heated too much, they are often fired.
As for television image-receiving devices, for example, the electron beam controller to be built in the neck of the color picture tube is generally composed of synthetic resin parts, and is adjacent to the power supply member that gives much heat. Therefore, the synthetic resin magnet rings to be in the electron beam controller must be incombustible. If not, the synthetic resin part will be fired due to the heat from the power supply member. For those reasons, the electron beam controller requires high flame retardancy.
Recently, there is increasing a great demand for flame-resistant synthetic resins to be used in producing many daily necessities. At present, therefore, in planning synthetic resin parts that constitute commercial products, it is the most important factor to make the synthetic resin parts incombustible.
In order to convert combustible synthetic resin materials into incombustible ones, for example, employable are any of (1) a technique of adding flame retardants to synthetic resin materials, (2) a technique of adding inorganic fillers to synthetic resin materials, (3) a technique of blending synthetic resin materials and flame-resistant polymers, and (4) a technique of co-polymerizing synthetic resin materials with flame-resistant monomers.
In general, any of those conventional techniques have heretofore been employed in order to produce flame-resistant products that meet various flame resistance standards (for example, UL Standards in USA), while selectively using suitable flame retardants, inorganic fillers, flame-resistant polymers, or flame-resistant monomers. Of those, halogen substances have heretofore been used in most cases.
Recently, the safety standards against fire have become severer and, in addition, the generation of toxic substances in fire has become highlighted. Especially in Western countries, the recent tendency is toward the inhibition of use of the conventional, halogen-containing flame retardants, inorganic fillers, flame-resistant polymers and flame-resistant monomers, and is even toward the inhibition of use of halogen substances in synthetic resin materials themselves.
This is because halogen substances, if fired, generate toxic substances. For example, when bromine compounds are fired, they give dioxin. It is well known that dioxin has severe negative influences on the environment.